In installations for covering containers or other articles in heat-shrink sleeves, it is useful to interpose an accumulator device between the reel carrying a heat-shrink sheath and the station where the sheath is used, with said accumulator device performing several roles. It enables variations in production rates to be absorbed, by avoiding the sheath being pulled too hard. It also enables the reel to be changed while leaving enough time for connecting a new sheath to the end of the old sheath.
Devices are known for accumulating flat material in flexible strip form, which devices comprise an accumulator box into which the strip penetrates and inside which it is laid flat to form a plurality of go-and-return plies. Such an accumulator device nevertheless suffers from certain drawbacks. Some flat materials tend to twist and do not take up spontaneously an arrangement in superposed plies, thereby leading to a shapeless jumble forming inside the box which can jam or damage the strip.